If by regular you mean constant, then yes I have constant fatigue but by defining this illness by just fatigue undermines all the work people are doing to get rid of the word fatigue as the main descriptor. As @Ambrosia_angel said, it is much more than that.

If by regular you mean constant, then yes I have constant fatigue but by defining this illness by just fatigue undermines all the work people are doing to get rid of the word fatigue as the main descriptor. As @Ambrosia_angel said, it is much more than that.

This is an interesting question. I have always assumed that fatigue is central to ME. And by fatigue I mean the total exhaustion after minimal effort that is completely unlike your experience in your pre-ME life. Something that no one who hasn't had it will understand! It seems to me from what I read and from my own experience that other symptoms, especially pain, can take over from fatigue as the outstanding symptom over time. Fatigue may be at the core, especially at the beginning, but there are a whole load of other symptoms we have to put up with that can supersede fatigue.

Now that I am managing my activity properly, I don't have constant fatigue. However, if I try to do normal things healthy people do like walk around in a grocery store, or garden, or more than very light housework, then I live in a constant state of utter exhaustion. It is not the fatigue people get from a long day at work or a heavy workout.

As others have said, ME is much, much more than fatigue. PEM, more than fatigue, is probably the defining feature of ME. Other features of the illness may be more debilitating -- cognitive dysfunction, pain, or immune dysfunction resulting in multiple infections.

Constant fatigue is 90% of my illness also. It is with me from the time I get up to the time I go to bed. Some days it is a drowsiness fatigue...some days my arms and legs feel heavy and some days I am just tired....I also have neuropathy in my feet and calves but that doesn't affect my daily life like the fatigue does.

While I always have some level of fatigue I've never considered it my "major" complaint. In fact sometimes early on I wondered if I was misdiagnosed since neurological problems have always been what I consider my most problematic symptoms. Then more info came out about those too so the definition fits better now. but the "suffocating, how" tired " do I have to be before my major organs shut down" fatigue is always there, if barely hidden under the surface or in full bloom snarling monster mode where I feel my energy drain out of my feet and I hope I can get to bed before I collapse.
When I was new to this game I took a walk by myself....big mistake when I nearly had to crawl home. I hate that stupid symptom.

M.E. is also distinguished from CFS in that multiple organ involvement, seizure activity, death, and autonomic nervous system dysfunction occur in M.E. and by definition, these simply do not occur in CFS. Perhaps the most important difference is that chronic fatigue, by definition occurs in 100% of CFS patients. In M.E. chronic fatigue is not an essential factor, but rapid CNS and muscular fatigability with a pathologically slow recovery or loss of stamina is an essential finding. In M.E., the illness, the disease process, its investigation and pathology starts on the day the patient ceases to be well. In CFS, the Atlanta based CDC has decreed that the disease process starts only on the first day of the sixth month.

There are multiple definitions which do not require it e.g. Ramsay ME, London ME, Jason et al's revision of the CCC, and the ME-ICC. All these definitions do require fatiguability and/or other post-exertional symptoms. Fatigue and fatiguability are not the same symptom. PENE and fatiguability are not synonymous either, but PENE does include fatiguability.

As others have said, the fatigue experienced is different than ordinary fatigue, and I think research by Jason's group confirms that fatigue is multi-dimensional and the experience is clearly different between patients when fatigued vs healthy controls when fatigued (same goes for what healthy people identify as "PEM"). Reducing "fatigue" levels to a single number may be misleading. Many patients feel that "fatigue" does not adequately describe what they experience, and try to distance themselves from it and the chronic fatigue shambles. Others may argue that exhaustion is just a synonym for fatigue.

As others have said, ME is much more than the sensation of "fatigue". Many patients report that even they do experience significant fatigue, it is not that (baseline) fatigue which particularly bothers them that much or stops them from doing more activities, it is all the other symptoms such as poor stamina, pathologically slow recovery period, post-exertional symptoms, neurocognitive impairment, orthostatic intolerance, flu-like symptoms, pain, etc.

Some patients also report that if they are rested enough and do not overexert themselves, they do not experience any "fatigue". I think it is relatively rare that a significantly affected patient does not experience any fatigue, mostly because the more severe one becomes, the more difficult it is for the body to sustain the activities of ordinary life. So even if they do not experience baseline fatigue, merely being awake is causing post-exertional symptoms which may include exhaustion. I suspect severely affected patients, the ones which experience PENE anyway*, are in a constant state of PENE.

* A few patients seem to be bedridden by severe post-viral fatigue without other major symptoms or even obvious PENE? I met someone like that once and she recovered in a few years.

A lot of chronic illness for example RA, MS have a component of fatigue attached so fatigue really isn't a defining characteristic of any illness. Personally knowing people with those illness I think its more secondary. MS, muscles are stiff, harder to move, more tiring. Arthritis causes joint pain, harder to move, more energy needed to accomplish the same task. There may be some other disease process involved too but just from knowing those with it, I think that is more true tiredness, you get over it with rest. Not so with this.
IMO the problem with labeling ME vs CFS vs ME CFS is nobody is talking about the same thing. Seems like some drs just make up their own thoughts about what happens in what they call "their " disease. Ie i read one that said multiple organ involvement isn't involved in CFS which is a load of dookie if you look on any CFS website's list of symptoms. That strident dogmatic who ha just muddies the issues

In my current opinion, people with well managed ME who are either mild or moderate, may not have chronic fatigue. They may have chronic fatiguability, but since they pace and take other strategies the fatigue can be missing. Byron Hyde made a point of this a long time ago. ME patients do not always have chronic fatigue. They still get PEM/PENE though if they crash.

I think this may be what happens with many patients who "recover" from "chronic fatigue" who have ME. That one symptom goes away but in at least some cases the disorder remains. ME is not chronic fatigue.

Chronic fatigue exists when the disorder is not well managed, which is the usual case, or when the demands of simply surviving keep pushing someone over the edge, typically a moderate to very severe patient.

David Bell did a study of 10 "recovered" patients with CFS (and possibly ME). They all still had symptoms other than chronic fatigue if I recall correctly.

IMO, fatigue happens when we overdo. For some, walking across the room is overdoing. For some, sitting upright in bed is overdoing. I've been there. There's no avoiding fatigue in that situation. Just staying alive is overdoing.

Now, I can walk across a room, do very light housework, drive a car, and tutor as long as I don't have to walk much. None of those things cause fatigue. But I can't go shopping, or do moderate housework, or walk 100 yds without significant PEM (which includes massive exhaustion). Too much mental work also causes fatigue, but to a lesser degree (unless I really overdo it).

I wouldn't consider myself a mild case of ME. I'm severely limited by the illness. I simply don't have constant fatigue because I don't overdo anymore. It was not possible to avoid overdoing when I was in a severe state. I can still easily overdo if I try to do even a small fraction of what I'd like to do, or what healthy people do.

I think ME/CFS invariably includes fatigue if patients try to maintain a normal life. Since most of us desire that more than anything, it's likely the majority of us are overdoing resulting in fatigue whether we're severe, moderate, or even mild.

ETA: I should probably add that fighting infections may also take all the energy we have and consequently result in fatigue even with the best activity management. Or maybe the cytokines associated with the infection are causing fatigue. I dunno. The whole thing is far too complicated.

if you read medical dictionary definitions, there are a variety of definitions for "fatigue", some of which include "asthenia" or muscle weakness, which would presumably include fatiguability.

The word is just so broad it covers every experience from the "cosy kitten" feeling healthy people describe (in Jason's paper which was mentioned above), to the ill/weak feeling people have when they have influenza, pneumonia, and liver failure, to various neurological weaknesses. And whatever is going on (I guess immune), which is also described as "fatigue", but is significant to very severe, in diseases such as Lupus and cancer.